#ifndef USEFUL_UTILS_H
#define USEFUL_UTILS_H
#include <algorithm>
#include <cstddef>
#include <iostream>
#include <stack>
#include <string>
#include <vector>

using namespace std;
// *
// Definition for a binary tree node.
struct TreeNode {
  int val;
  TreeNode *left;
  TreeNode *right;
  TreeNode() : val(0), left(nullptr), right(nullptr) {}
  TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
  TreeNode(int x, TreeNode *left, TreeNode *right)
      : val(x), left(left), right(right) {}
};
#endif
